1. Field of the Invention
This invention relates in general to transmission systems and in particular to a novel transmission system for attenuating unbalanced to ground currents in a transmission line.
2. Description of the Prior Art
Transmission systems are shown for example in U.S. Pat. No. 1,915,442. When PCM-Technique was introduced at the local level of telephone networks the problem of assuring safe transmission of signals with minimum cable cost became important. When pair of conductors are used in the form of doubles or quadruples which are assembled to form a large group of conductors, cross-talk between the individual pair of lines has an interfering effect due to the coupling of pulses from one pair of conductors into another pair of conductors within the regenerator and thus originally trnsmitted pulse information can be erroneously detected. For this reason it has been necessary to apply only a group of pair of lines for one transmission direction in other words those transmitting intelligence in the out-going direction and to have another separate pair of conductor group which is used in the receiving direction. Although the groups may be put into one cable it is common to use separate cables, however, cross-talk interference is still present and constitutes a problem. One solution which is very expensive is to use separate coaxial conductor cables instead of cables containing ground symmetric double conductors. However such approach is much more expensive than utilizing cables.